<template>
	<view>
		<view class="u-wrap" style="border-top:1px solid #ddd">

			<view class="u-menu-wrap" v-if="tabbar">
				<scroll-view scroll-y scroll-with-animation class="u-tab-view menu-scroll-view" :scroll-top="scrollTop"
					style="background-color: #f6f6f6;">
					<view v-for="(item,index) in tabbar" class="u-tab-item"
						:class="[current==index ? 'u-tab-item-active' : '']" :data-current="index"
						@tap.stop="swichMenu(index)">
						<text class="u-line-1">{{item.name}}</text>
					</view>
				</scroll-view>
				<block v-for="(item,index) in tabbar" :key="index">
					<scroll-view scroll-y class="right-box" v-if="current==item.id" style="background-color: #fff;">
						<view class="page-view">
							<view class="class-item">
								<view class="item-container">
									<view class="thumb-box" v-for="(item1, index1) in item['child']" :key="index1"
										@click="checkLy(item1.id,item1.name)">
										<view class="fdata">
											<view class="item-menu-name">{{item1.name}}</view>

										</view>
									</view>

								</view>

							</view>
						</view>
					</scroll-view>
				</block>
			</view>
		</view>
	</view>
</template>

<script>
	import {
		getly
	} from 'api/api.js';
	export default {
		name: 'city',
		data() {
			return {
				tabbar: [],
				pageloading: true,
				chrild_current: 0,
				current: 1,
				scrollTop: 0,
				menuHeight: 0,
				menuItemHeight: 0,

			}
		},
		mounted(options) {
			let _this = this;
			_this.getForumList()
		},

		methods: {
			checkLy(id,name) {
				let pages = getCurrentPages();
				let prevPage = pages[pages.length - 2];
				prevPage.$vm.backUpdatePages({ 
					id: id,
					name:name
				})
				uni.navigateBack();
			},

			getForumList() {
				let _this = this
				getly({}).then(r => {
					if (r.data.code == 200) {
						_this.tabbar = r.data.data
					}
				})
			},
			// 点击左边的栏目切换
			async swichMenu(index) {
				if (index == this.current) return;
				this.current = index;
				// 如果为0，意味着尚未初始化
				if (this.menuHeight == 0 || this.menuItemHeight == 0) {
					await this.getElRect('menu-scroll-view', 'menuHeight');
					await this.getElRect('u-tab-item', 'menuItemHeight');
				}
				// 将菜单菜单活动item垂直居中
				this.scrollTop = index * this.menuItemHeight + this.menuItemHeight / 2 - this.menuHeight / 2;
			},
			// 获取一个目标元素的高度
			getElRect(elClass, dataVal) {
				new Promise((resolve, reject) => {
					const query = uni.createSelectorQuery().in(this);
					query.select('.' + elClass).fields({
						size: true
					}, res => {
						// 如果节点尚未生成，res值为null，循环调用执行
						if (!res) {
							setTimeout(() => {
								this.getElRect(elClass);
							}, 10);
							return;
						}
						this[dataVal] = res.height;
					}).exec();
				})
			}
		}
	}
</script>


<style lang="scss" scoped>
	.page-view {
		padding-bottom: 170rpx !important;
	}

	.checkCity {
		.city-box {
			border-bottom: 2rpx solid #eee;
			padding: 30rpx;

			&-title {
				color: #999;
				font-size: 34rpx;
				margin-bottom: 20rpx;
			}

			.cityList {
				display: flex;
				flex-wrap: wrap;

				.cityItem {
					width: 48%;
					margin: 20rpx 1%;
				}
			}
		}
	}

	.u-wrap {
		height: calc(100vh);
		/* #ifdef H5 */
		height: calc(100vh - var(--window-top));
		/* #endif */
		display: flex;
		flex-direction: column;
	}

	.u-search-box {
		padding: 18rpx 30rpx;
	}

	.u-menu-wrap {
		flex: 1;
		display: flex;
		overflow: hidden;
	}

	.u-search-inner {
		background-color: rgb(234, 234, 234);
		border-radius: 100rpx;
		display: flex;
		align-items: center;
		padding: 10rpx 16rpx;
	}

	.u-search-text {
		font-size: 26rpx;
		color: $u-tips-color;
		margin-left: 10rpx;
	}

	.u-tab-view {
		width: 300rpx;
		height: 100%;
	}

	.u-tab-item {
		height: 110rpx;
		background: #f6f6f6;
		box-sizing: border-box;
		display: flex;
		align-items: center;
		justify-content: center;
		font-size: 26rpx;
		color: #444;
		font-weight: 400;
		line-height: 1;
	}

	.u-tab-item-active {
		position: relative;
		color: #000;
		font-size: 30rpx;
		font-weight: 600;
		background: #fff;
	}

	.u-tab-item-active::before {
		content: "";
		position: absolute;
		border-left: 4px solid $base-color;
		height: 32rpx;
		left: 0;
		top: 39rpx;
	}

	.u-tab-view {
		height: 100%;
	}

	.right-box {
		background-color: rgb(250, 250, 250);
	}

	.page-view {
		padding: 0 16rpx;
		padding-left: 0;
	}

	.class-item {
		margin-bottom: 30rpx;
		background-color: #fff;
		padding: 0 16rpx;
		border-radius: 8rpx;
	}

	.item-title {
		font-size: 26rpx;
		color: $u-main-color;
		font-weight: bold;
	}

	.item-menu-name {
		font-weight: normal;
		font-size: 32rpx;
		color: $u-main-color;
	}

	.desc {
		color: #999;
		font-size: 24rpx;
		margin-top: 5rpx;
	}


	.thumb-box {
		width: 100%;
		padding: 30rpx;
		border-bottom: 1px solid #eee;
		display: flex;
		justify-content: space-between;
		align-items: center;

		.icon-chenggong {
			color: #1e4fe2;
			font-size: 38rpx;
		}
	}

	.item-menu-image {
		width: 120rpx;
		height: 120rpx;
	}


	.defforum {
		background-color: #1e4fe2;
		color: #fff;
		font-size: 28rpx;
		text-align: center;
		height: 70rpx;
		line-height: 70rpx;
		opacity: .8;
		border-radius: 10rpx;
		margin: 40rpx 0;
	}
</style>